Process of making spelter.



UNITE STAT S w PATENT OFFICE."

OSKAR NAGEL, OFNEW YORK, N. Y.

PROCESS OF MAKINGSPELTER.

SPECIFICATION forming part of Letters Patent No. 699,969, dated May 13, 1902.

Application filed November 13, 1901. Serial No. 82,134; (No specimens.)

To aZZ whom it may concern:

Be itknown that I, OSKARNAGEL, a subject of the Emperor of Austria lIungary, residing in the borough of Manhattan, city of New York, State of New York, have invented a certain new and useful Process of Making Spelter, of which the following is a description. My invention relates to an improved process for making spelter.

The invention has been specially designed for the purpose of providing a process by which spelter can be produced in ablast-furnace with consequent economy in the cost of p'rbduction; but the invention is not limited to the making of spelter in such an apparatus, but can becarried out in connection with the condensation of zinc-vapors obtained by any other reducing process or 'reactiontas,

, for instance, by heating blende with iron or iron-silicate, (Fe SiO I am of course aware that during the past fifty years the possibility of producing spelter in ablast-furnacehas been'frequently suggested andnumerous experiments have beeninade to accomplish that result; butso far as I know no one prior to myself succeeded in condensing'zinc in such an apparatus to a pure liquidmass. In all of the prior attempts to produce spelter in a blast-furnace, so'far as I know, the result has been the production of zinc-dust,which,from a metallurgical standpoint, can only be regarded as an intermediate product capable, itis true, of being converted to spelter by further reduction.

In experimenting for the purpose of verifying the commonly-accepted explanation of the cause of the production of zinc-dust where the attempt has been made to obtain spelter in a blast-furnace I have found that zinc-vapors, if diluted with indifierent or inactive gases, such as nitrogen, will in every instance condense to dust instead of to liquid spelter, and I have further ascertained that if in addition to such indifferent or inactive gases the zinc-vapors arediluted with oxidizinggases, such as oxygen or carbonic acid, a corresponding part of the resulting dust will be immediately oxidized. tempts referred to indifferent and oxidizing gases have been inevitably present, since the reducing operation was always carried on in In the prior at the presence of air blown into and through a mixture of ore and coal, coke, or charcoal.

I have discovered that spelter can be made in ablast-furnace if indifferent, inactive, and

oxidizing gases are excluded from the evolved Vapors, as well in the furnace itself as in the condensing apparatus, by employing onlya gas which performs areducing operation and which passes with the'vapors to the condensingapparatus. When such agas is employed for performing a reducing operation in a blastfurnace, the evolved zinc vapors will condense to a liquid mass free from dust, the resulting spelter obtained being as pure as that which is now secured in theordinary processes using retorts'and muffles.

' The'invention consists in subjecting a suitable zinc ore, preferably mixed with coal, to the action of water-gas which is practically free from inert," indifferent, and oxidizing gases, and by which the zinc willbe reduced and as an evolved vapor will be condensed in an atmosphere which permits the formation of pure spelter. The active reducing-gas which I employ in my process is advantageously and preferably heated before being injectedinto the furnace, thereby practically doing away with the necessity of using other fuel and, in consequence, overcoming the greatest dificulty with which prior experimenters met-to wit, the dilution and oxidation of the zinc-vapors by combustion-gases.

In'the preferred embodiment of the'invention, therefore, the active reducing watergas, being first heated to'the necessaryt'e-mperature, is injected into the furnace,which is charged with a dry or baked mixture in the proportion of one part of coal and seven parts readily effected, taking place with a yield of i from ninety to ninety-five per cent. of zinc,

containing about .045 per cent. lead and .04 per cent. iron.

In a more specific sense, therefore, the invention consists in injecting heated watergas into the zinc ore in a blast-furnace and, preferably, for the reasons stated, into a mixture of zinc ore and coal with the reactions indicated.

The gas which I use for reduction and for the atmosphere of condensation is, as stated, water-gas, which contains about equal volumes of carbon monoxid and hydrogen, both of which gases are eminently reducing. The water-gas, which can be cheaply prepared by well-known methods, before being injected into the blast-furnace is first heated in ovens of any desired form, which ovens are heated by the waste reduction-gases (coming from the condensation apparatus) or by producergas, which is produced intermediately with the water-gas by well-known methods. The reducing-gas is preferably forced into the furnace by means of a fan or blower the capacity of which is properly calculated to accommodate the desired bulk of gas at the temperature used. Thus 1.5 tons of water-gas at 0 centigrade has a bulk of about two thousand two hundred and thirty-two cubic meters. At 850 centigrade the same weight of gas occupies a space of eight thousand nine hundred and thirty cubic meters, and at 1,000 centigrade (which is about the temperature which I prefer to employ in my process) the same weight of gas will occupy ten thousand four hundred and fifteen cubic meters. Consequently the fan or blower is increased or reduced in size as the temperature of the gas used in the process may be high or low. In order to prevent the dilution of the reducinggas by carbonic acid formed during and by the reduction process, the zinc ore, as stated, is preferably mixed and eventually baked with coal in about the proportions above indicated, so that during the reduction the carbonic acid is reduced in statu nascenii to carbon monoxid.

Any suitable apparatus can be used for carrying my improved process into effect, and approved forms of furnaces used in the reduction of other metals can be conveniently employed. Thus for the reduction of ores of relatively large size the furnace may be constructed similarly to the ordinary shaft of a lead-furnace, while for small-sized ores the furnace may be constructed upon the lines leads to the condensation apparatus, which may conveniently be arranged like the apparatus now used in the arts for the condensation of mercury. With a furnace of the capacity of twenty-five tons of zinc oxid or a corresponding amount of oxydic ore about five tons of the oxid will be reduced in from four and one-half to five hours, it being understood that the temperature of the watergas injected is about 1,000 centigrade.

By the expression oxydic ore above used by me I mean any natural or roasted material containing zinc oxid, carbonate, silicate or hydrate, or mixtures of the same-such as roasted blende of any grade, roasted galena blende, franklinite, willemite, zincite, calamine, smit-hsonite, hydrozincite, &c.

I find in practice that 1.5 tons of watergas containing 1.4 tons of carbon monoxid and .1 ton of hydrogen and occupyinga bulk of ten thousand four hundred and fifteen cubic meters at 1,000 centigrade, as before stated, will be sufiiicient for the reduction of 8.1 tons of zinc oxid or roasted good blende or the equivalent amount of any other suitable zinc ore. I

In carrying the process into effect the furnace is first charged through the hopper with the ore or mixture of ore and coal or other suitable hydrocarbon in the proportions stated, and the hot water-gas coming from the producer or gasometer and of the proper temperature is passed through the ore, carrying the zinc-vapors into the condensation apparatus. Preferably a small dust-chamber is interposed between the furnace-and the condensation apparatus, in which will be collected any dust which may have become mechanically entrained and carried over with the vapors. The spelter will be condensed in the condensation apparatus at a temperature of from 415 to 550 centigrade andcan be removed either from time to time or continuously, as may be desired, being received in reserve tanks or cast in suitable forms. The hot waste gases passing from the condensation apparatus being composed of carbon monoxid and hydrogen can be burned with air, and thus used for heating the ovens or for any other purpose.

While I have described my invention as being carried out in connection with a blastfurnace and as preferably utilizing an active reducing-gas in a highly-heated form, it will be understood that the reactions may take place in other forms of apparatus and that the reducing-gas need not be in a heated condition. Thus the ore may be treated in furnaces which are heated exteriorly, or, instead, the material may be heated electrically, in both of which cases the reducing-gas need not be injected into the furnace in a superheated condition. As before indicated, it will also be understood that my improved process can be carried out in connection with the condensation of zinc-vapors obtained by any other process or reaction-as, for example, by heating blende with iron or iron silicate, (Fe SiO It will finally be understood that zinc-vapors prepared in a blast-furnace as I have described can, if desired, be oxidizedby a current of air to produce pure oxid of zinc instead of being condensed to spelter in a condensation apparatus.

I am aware that prior to my invention the use of carbon monoxid for zinc reduction had been suggested, the carbon monoxid being prepared by blowing air overcoal. With such processes an objectionably large percentage of nitrogen is present, whereby the reducing-gas will be so diluted that a condensation of zinc to liquid metal is impossible. By employing water-gas, as I suggest, my zinc atmosphere contains over sixtyv per Hcent. more zinc than any carbon-monoxid atmosphere could possibly contain. My atmos-. phere is not only higher in concentration than in the prior processes, but has a much lower specific gravity, since hydrogen replaces the nitrogen of the other processes, thereby allowing a condensation to liquid metal.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is as follows:

1. An improved process for condensing zincvapors to spelter, which consists in cooling the vapors in an atmosphere of water-gas,snbstantially as set forth.

2. An'improved process for reducing zinc oxydic ores,which consists in subjecting the material in the presence of heat to the reducing effect of water-gas, substantially as set forth.

3. An improved process for reducing zinc oxydic ores, which consists in subjecting the material to the reducing effect of heated water-gas, substantially as set forth.

- 4. An improved process of making spelter from zinc oxydic ores, which consists in subjecting the material in the presence of heat to the reducing efiect of water-gas, and in cooling the resulting zinc-vapors in an atmosphere of such gas, substantially as set forth.

5. An improved process of making spelter from zinc oxydic ores, which consists in subjecting the material to the reducing effect of heated water-gas, and in cooling the resulting zinc-vapors in an atmosphere of suchgas,

substantially as set forth.

6. An improved process of making spelter from zinc oxydic ores or zincic materials,

which consists in subjectinga mixture of such material and coal in the presence of heat to the reducing effect of water-gas, and in cool ving the resulting zinc-vaporsin an atmos= phere of such gas, substantially as set-forth; This specification signed and witnessed this 7th day of November, 1901.

OSKAR NAGEL.

Witnesses:

FRANK L. DYER, JNo. R0131. TAYLOR. 

